4 files changed, 46 insertions, 3 deletions
diff --git a/basics/opt/deep_copy_opt.py b/basics/opt/deep_copy_opt.py
new file mode 100644
index 0000000..d537b15
--- /dev/null
+++ b/basics/opt/deep_copy_opt.py
@@ -0,0 +1,26 @@
+
+_dispatcher = {}
+
+def _copy_list(_l):
+    ret = _l.copy()
+    for idx, item in enumerate(ret):
+        cp = _dispatcher.get(type(item))
+        if cp is not None:
+            ret[idx] = cp(item)
+    return ret
+_dispatcher[list] = _copy_list
+
+def _copy_dict(d):
+    ret = d.copy()
+    for key, value in ret.items():
+        cp = _dispatcher.get(type(value))
+        if cp is not None:
+            ret[key] = cp(value)
+
+    return ret
+_dispatcher[dict] = _copy_dict
+
+
+if __name__ == '__main__':
+    l = [1, 2, 3]
+    _copy_list(l)
+\ No newline at end of file
diff --git a/basics/python_basics.py b/basics/python_basics.py
index bf780cc..34b43e2 100644
--- a/basics/python_basics.py
+++ b/basics/python_basics.py
@@ -1,4 +1,6 @@
 
+import copy
+
 def check_num_id(i):
     a = i
     b = i
@@ -8,3 +10,4 @@ def check_num_id(i):
 if __name__ == '__main__':
     for i in range(200, 260):
         check_num_id(i)
+    copy.deepcopy()
diff --git a/finance/discount_time_value.py b/finance/discount_time_value.py
new file mode 100644
index 0000000..d3b88df
--- /dev/null
+++ b/finance/discount_time_value.py
@@ -0,0 +1,14 @@
+
+
+def npv(pays, r):
+    return sum([pay/((1+r)**(i+1)) for i, pay in enumerate(pays)])
+
+
+if __name__ == '__main__':
+    pays = [236.8, 236.8+1000]
+    r = 0.2368
+    print(npv(pays, r))
+
+    pays = [192.06, 192.06+1100]
+    r = 0.1746
+    print(npv(pays, r))
diff --git a/finance/equal_principal_interest.py b/finance/equal_principal_interest.py
index 035fd8c..2954260 100644
--- a/finance/equal_principal_interest.py
+++ b/finance/equal_principal_interest.py
@@ -12,8 +12,8 @@ def monthly_analysis(p, r, n):
 
 
 if __name__ == '__main__':
-    p = 600000
-    r = 0.06
-    n = 20*12
+    p = 2000000
+    r = 0.055
+    n = 30*12
     monthly_analysis(p, r, n)